Stucco sign with metal lettering

It looks to me like it is steel/stainless steel with an oil rubbed bronze coating over it to protect it and get the desired color with it being durable. This is typically done via powder coating.

First step is to determine what the metal is IMO.

1.) Tap it to determine thickness of metal. This will narrow down metal type significantly.
2.) Use a small amount of acetone on a rag and rub it on the underside of a letter where it cant be seen by people. If its a powder coating as I assume it is the coating will be cleaned easily and give you a consistent color. (If you believe the material is copper or brass and the color is the patina then follow the same procedure with muriatic acid instead of acetone)
3.) Take that info and walk into a sign making company and they should know exactly what it is.
4.) Once you know what it is. Google search for how to clean the stains from it and what chemicals can be applied without stripping the patina.

Charge a premium for this type of work. Very few people do troubleshooting like this. I often clean architectural fountains with numerous different types of exterior/submersible rated metals that react to different products.

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Just do a small test spot on one of the letters…it will let you know.

I bet there will be no reaction at all…

And, you could wipe them with WD40 first, wash the sign, rinse and wipe again with WD40.

Could’ve been there prior to washing depending on how bad it was. When it’s that light I hit it with Barkeeper’s friend foam and my softest brush. Don’t let it dry. If it’s still there, but noticeably less I’ll hit it again. If it hadn’t budged I move up to oxalic or F9 for most metals.

Soft brush is key. Stiff brush will leave a “clean” shadow. Then you’ve gotta blend. It’s a mess. Start off light, escalate if necessary.

This stuff is borderline magical.

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Thanks squid. And thanks everyone. Unfortunately results were not great. I tried the barkeeper’s on a spot in the back of the building and it completely stripped the paint and “bleached” the surface. I’m talking pure white. Not to mention that when I went to pre wet the surface I noticed additional dried bleach streaks underneath the windows. Completely invisible dry but very noticeable when wet. At this point I decided to cut my losses and offer to have the section painted. Didn’t even touch the sign as a simple rinse down started cracking the surface. Luckily this is my dad’s office building and you can’t see any issues from the steet or parking lot so I’m not super screwed. I’d like to at the very least use it as a learning experience but I don’t know what I can take from it. I’ve done stucco before and had it turn out fine. I probably rinsed for an hour on this job to get the suds out. No exaggeration. I just don’t know what I could have done to prevent what happened And I’m also at a loss as to how to fix what I did without stripping the surface. I’m a little tempted to just get a couple of 8gpm machines, a 60" surface cleaner and only work on concrete. I just can’t imagine what I would do if this had happened to the front of a customer’s house. Maybe I’m overreacting idk. It looks good at a distance anyone would see it.

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Oxalic will do this if left to dry. The amount of oxalic in Barkeeper’s friend is super low… it’s super mild stuff. do you have pics?

I don’t have any pics but I pre wet the surface and rinsed it after 20 seconds. Just looks like beige stucco with a white streak in it.

Get pics if you can. I’ve put Barkeeper’s friend on small rust spots and mud dobber nests on stucco before I ever started washing only to remove it an hour or more later with never even a remotely similar problem.

I’d like to trouble shoot why that happened to you.

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Will do. I’m back home now but I’ll run by this afternoon to grab some pics. I appreciate you taking the time to walk me through this.

Only thing I can think of is that I spread around some dried bleach ,(but that doesn’t make any sense) or that maybe the paint is just so old that I brushed it right off.

What are you using for surfactant and how much?

I xjetted about 7-8% SH with an ounce of elemonator per gallon. Could’ve been a bit too much for stucco I see now in hindsight.

I am lost…what happened?

Thought that you were asking about a sign.

Then you mention the window.

Now, I see you are talking about the building. And, you said a test spot messed up…but you are talking about repainting the building???

The reason I ask is because you can get Snow white patches and streaks if it’s not all rinsed out. I’ll wait to see pics.

Broken record…You will make more money walking away from anything you have to ask a questions about, have a gut feeling about, or just don’t want to deal with. I always always always walk away from stucco, oxidation, green, blue, red, or brown houses.

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True. But at that rate I’d just be doing concrete. Which I might be okay with and I’m contemplating adapting my rig to it. Y’all must be lucky with all the vinyl houses in your area, but in the door to door marketing I’ve done, not a single, solitary house had a vinyl exterior. Everything is brick or stucco. The only time I see vinyl is at large apartment complexes and low-income areas. That said, every single one of these houses had driveways ranging from 3,000 to 11,000 sq. ft.

@squidskc Wasn’t able to get back out there today but I’m on the job Monday and will go see what the deal is.

@JimLuke Started with questions about the sign, ended up passing on it because it was so brittle it started falling apart just wetting it, and then had questions about the stucco building I washed alongside it.

Only problem with Vaseline is after I use it and it is sitting in my toolbox in the hot truck and it melts and gets all over everything. Yuck. Maybe switch to high temp wheel bearing grease or something that won’t melt. But those tend to be gray and ugly.

Zip-lock bag, i do that for my sunblock

??? What kind do you buy. It comes in a jar, never had one melt and it gets pretty hot here.

That’s interesting. Thanks for that. I assumed it was a universal thing. Maybe there are different formulations. Never crossed my mind. I just get the smallest little travel size I can find. They always melt and fall over and that cap on the tub is useless for containing a liquid. I could put it in a ziploc, but then I’d just have a disgusting plastic bag full of vasoline.